Tom van der Woerdt:
Should they actually be blocked though?
I mean, it's a lot of relays, but they're also contributing actual exit bandwidth and it's not like they're spread over hundreds of /16s.
I was just about to write a bit of clarification actually: They shouldn't be in a position to be able to really de-anon anyone via sybil, the oldest relays seem to be 3 days old, so there's still at least another 4 until they can get Guard, and that will still take a while to get users on it. Not to mention tor doesn't build circuits with more than one node on the same /16 (although now this batch has taken on another range) Though, they could have already set up a number of guards prior to this that may not be obviously linkable to the same entity. Assuming this is not the case, for now they just have a better advantage at sniffing/injecting as an exit, but you should already be (trying to) use encryption as much as possible.
With intentions and scenarios unknown, it could also be someone who wants to help, there /was/ a call for exits not too long ago, after all.
So, If you're a relay, you shouldn't bother trying to filter these, the Authorities should figure it out. If you're a client, I guess that's up to you, there might not be a whole lot of benefit if you do.